SocketStream

Introduction

SocketStream is a new breed of web framework that uses websockets to push data to the browser in 'realtime'. It makes it easy to create blazing-fast, rich interfaces which behave more like desktop apps than traditional web apps of the past.

By taking care of the basics, SocketStream frees you up to focus on building your social/chat app, multiplayer game, trading platform, sales dashboard, or any kind of web app that needs to display realtime streaming data. All personal tastes (e.g. Vanilla JS vs CoffeeScript, Stylus vs Less) are catered for with optional npm modules that integrate perfectly in seconds, without bloating the core.

Why SocketStream?

Building a simple chat app that uses websockets is easy.
Building a rich, non-trivial, responsive realtime UI without ending up with a mess of code is hard.

SocketStream eases the pain by:

Integrating best-of-breed modules to increase productivity

Providing a sensible place to put everything

Accelerating development with Live Reload and (optional) support for Stylus, Jade, etc

Accelerating deployment with integrated asset packing and CDN support

Organizing spaghetti client-side code into modules you can require()

Working well with all major client-side frameworks (e.g. Backbone, Ember, Angular)

Making it easy to hookup Redis, MongoDB, CouchDB or other storage engines

Providing an active community to answer your question

No other realtime framework plays as well with the entire Node.js ecosystem, or gives you the flexibility to swap-out code pre-processors, template engines or even websocket transports until you have the very best custom stack for your app.

SocketStream is MIT licensed.

Status

SocketStream 0.3 is now stable enough for production use internally (behind a firewall). Several pioneering users are successfully hosting external apps in production, though we ask you to use caution and appreciate that SocketStream is new software which has yet to be battle hardened.

SocketStream 0.3 will continue to be updated with bug fixes and minor feature enhancements. All major development work is now going into SocketStream 0.4 (read announcement) which builds upon the features and ideas in 0.3.

How does it work?

SocketStream sends all the static HTML, CSS and client-side code your app needs the first time a user visits your site (all automatically compressed in production mode).

From then on all application data is sent and received via the websocket (or websocket fallbacks), instantly established when the client connects and automatically re-established if broken. Normally this will be in JSON RPC format, but SocketStream 0.3 allows you to use different Request Responders (message handlers) depending upon the task at hand.

All this means no more connection latency, HTTP header overhead, polling, or clunky AJAX. Just true bi-directional, asynchronous, 'streaming' communication between client and server.

Getting Started

Ready to give it a whirl? Install Node 0.8.X then get SocketStream from npm:

[sudo] npm install -g socketstream

To generate a new empty SocketStream project type:

socketstream new <name_of_your_project>

Tip: Type socketstream -h to view all available options

Install the bundled (optional) dependencies:

cd <name_of_your_project>
[sudo] npm install

To start your app simply type:

node app.js

If all goes well you'll see the SocketStream banner coming up, then you're ready to visit your new app at:

http://localhost:3000

What can I create with it?

SocketStream is a perfect fit for all manner of modern applications which require realtime data (chat, stock trading, location monitoring, analytics, etc). It's also a great platform for building realtime HTML5 games.

However, it would make a poor choice for a blog or other content-rich site which requires unique URLs for search engine optimization.

Demo Apps

Example 1: Basic RPC

SocketStream 0.3 supports multiple ways to send messages to and from the server. The most common of which, JSON-over-RPC, is included by default. An RPC call can be invoked on the server by calling ss.rpc() in the browser.

For example, let's write a simple server-side function which squares a number:

Restart the server and then invoke this function from the browser's command line:

ss.rpc('app.square', 25)

You'll see the answer 625 logged to the console by default. The eagle-eyed among you will notice ss.rpc('app.square', 25) actually returned undefined. That's fine. We're only interested in the asynchronous response sent from the server once it has processed your request.

You may be wondering why app.square? Because we're invoking the square action/function in the app.js file. If you had written a resize action in /server/rpc/image/processor.js you'd call it with ss.rpc('image.processor.resize'). This naming convention allows you to create as many sub-directories as you wish to organize your code.

Now let's write some code in the client to do more with this response:

// client/code/app/demo.js// define the number to square (vars are local to this file by default)var number =25;
ss.rpc('app.square', number, function(response){
alert(number +' squared is '+ response);
});

Once you save the file, the browser will automatically reload and you'll see an alert box popup with the following:

Extending SocketStream

Other

FAQs?

What browsers will SocketStream work with?

SocketStream works best with Chrome, Safari, Firefox 6 (and above) which all support native websockets. It is also compatible with older versions of Firefox and IE thanks to Socket.IO fallback transports. In addition, iPads and iPhones using Mobile Safari (iOS 4.2 and above) are fully supported, even over 3G.

How can I make my app auto-restart when /server code changes?

Install the excellent 'nodemon' module with sudo npm install -g nodemon then start your app with nodemon app.js. A .nodemonignore file has already been created for you with the optimal settings. This feature is very useful when developing your app.

How can I configure Socket.IO?

You may fully configure the Socket.IO server and client libraries like so:

Will it run on Windows?

How can I share code between client and server?

Does SocketStream support models?

No. Not in the core.

Instead we offer a powerful API to allow developers to experiment with opinionated approaches to model synching, client-side APIs (e.g. simulating MongoDB in the browser), serialization protocols, and much more.

Several third-party add-on modules (for Backbone, Angular and more) are now in active development by the community. Please search our Google Group for details.

Ideally we'd like to end up with one great, well-maintained module for each major client-side framework which allows for seamless high-speed model syncing to your choice of persistent store. The best modules will be featured on our website in the near future, giving you the ability to pick the best tools for your particular use-case.

Should I use Redis?

Yes. SocketStream installs the Redis driver by default but does not require Redis to be running when developing your app (for convenience sake). However, as soon as you want to host your app for real, you need to be using Redis.

Redis is used in two areas of SocketStream - session storage and internal pubsub (used by ss.publish commands). You can enable Redis in your app with the following commands in your app.js file:

ss.session.store.use('redis');
ss.publish.transport.use('redis');

Pass any config as the second argument to either of the above commands as so:

{host: 'localhost', port: 6379, pass: 'myOptionalPass', db: 3}

How about scaling?

SocketStream 0.3 makes a big assumption in order to maximize speed and reduce code complexity: All incoming connections with the same session should be routed to the same server (also known as Sticky Sessions). The session details are stored in memory and then optionally saved to Redis to preserve the session should the node fail.

Front end scaling can be achieved using a combination of different websocket transports (such as the forthcoming Pusher Pipe module) and optional features we intend to introduce in the future.

Back end scaling has yet to be properly documented, but we're keen to continue looking into ways to use ZeroMQ and also Hook IO. We will make sure back end scaling is as easy and flexible as possible, but it will no longer be a feature of the framework itself.

Upcoming Speaking Events

Developing on the SocketStream core

SocketStream 0.3 is primarily written in CoffeeScript which is 'pre-compiled' into JavaScript using make build. If you're actively developing on the code make sure you install the dev dependencies first (just clone the project and type sudo npm link).

To avoid having to continually type make build every time you make a change, pass the SS_DEV=1 environment variable when running your SocketStream app:

$ SS_DEV=1 node app.js

This instructs your app to run the CoffeeScript code in <socketstream_root>/src directly, so you only need to restart the server to see your changes.

Note: SocketStream 0.4 will be written in vanilla JavaScript. Follow @socketstream to be the first to know when it's available on Github

Recommended alternatives to SocketStream

We hope you'll find SocketStream is a great fit for your app, but if it's not exactly what you're looking for, consider these alternatives:

If SEO is important to you, take a look at Derby. If you're looking for an end-to-end commercial solution, Meteor is the best out there.

Testing

There are a number of Mocha tests starting to appear for parts of the API which are unlikely to change. To run them type:

$ make test

More tests coming soon. Contributions very much appreciated.

Contributors

Creator and lead developer: Owen Barnes.

Special thanks to Paul Jensen for contributing code, ideas and testing early prototypes. Big thanks also to Addy Osmani for help with everything JavaScript related, Alan Milford for providing initial demos, and Craig Jordan Muir for designing the awesome new SocketStream logo.

Thanks also to the many who have contributed code and ideas. We plan to properly feature contributors on our website in the near future.